Parasitically coupled folded dipole multi-band antenna
An antenna is provided which includes a primary folded dipole element and a feed for the primary folded dipole element. The primary folded dipole element is operable to resonate at a first frequency range. A parasitic dipole element is located within the primary folded dipole element and is spaced therefrom. The parasitic dipole element is operable to resonate at a frequency range that is higher than the first frequency range. Additional parasitic dipole elements may be located within the primary folded dipole element and spaced therefrom to resonate at different frequency ranges.
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Priority for this application is claimed based upon provisional application Ser. No. 60/612,321, filed Sep. 23, 2004, the disclosure of which provisional application is incorporated herein.
FIELD OF THE INVENTIONThe present invention concerns a novel antenna, and, more particularly, a parasitically coupled folded dipole multi-band antenna.
BACKGROUND OF THE INVENTIONFor many antenna applications it is desirable to have a single antenna that will function on two or more frequency bands. Many techniques exist which enable double or multiple resonances from a single antenna. They include multiple elements fed in parallel, single elements with wave traps which allow certain frequencies to use only a portion of the element, and parasitic coupled elements.
Parasitic elements typically have one driven element, for example a simple half wave length dipole antenna at the lowest frequency, and secondary elements which are resonant ½ wavelengths at different frequencies, positioned near the first element. Through inductive and/or capacitive coupling, the responses of the secondary elements can be seen at the first element's feed point. With proper adjustment of the lengths and the spacing of the element an effective multi-band antenna can be realized.
It is an object of the present invention to provide an efficient multi-band antenna, that is relatively simple in construction and easy to manufacture.
SUMMARY OF THE INVENTIONIn accordance with the present invention, an antenna is provided which comprises a primary folded dipole element and a feed for the primary folded dipole element. The primary folded dipole element is operable to resonate at a first frequency range. A first parasitic dipole element is located within the primary folded dipole element and is spaced therefrom. The first parasitic dipole element is operable to resonate at a frequency range that is higher than the first frequency range.
In one embodiment, the first parasitic dipole element is a folded dipole element that is positioned in an offset relationship to the primary folded dipole element.
In one embodiment, a second parasitic dipole element is provided and is located within and spaced from the primary folded dipole element. The second parasitic element is operable to resonate at a frequency range higher than the frequency range of the first parasitic element.
In one embodiment, the primary folded dipole element and the first parasitic dipole element are formed on a printed circuit board.
In one embodiment, the primary folded dipole element is rectangular and includes dipole extensions which extend from the rectangle to provide a desired resonance.
In one embodiment, the primary folded dipole element and the first parasitic dipole element with the extensions are formed on a printed circuit board. The primary folded dipole element with the extensions and the first parasitic dipole element are formed of metal, with the metal extensions having a distal end with the metal extensions increasing in width toward that distal end to provide a wider bandwidth response.
A more detailed explanation of the invention is provided in the following description and claims, and is illustrated in the accompanying drawings.
Now referring to
A folded dipole is similar to a standard single wire dipole but there is a second wire connected in parallel to the first wire. The configuration of a folded dipole looks like a wide flat loop with the feed in the center of the first wire. The length of the folded dipole is approximately ½ wavelength at the resonant frequency. The impedance of the folded dipole can be adjusted by varying the spacing of the parallel wires and the diameters of the wires. The folded dipole is used when the impedance of the antenna needs to be raised. In some instances it is desirable to use a partial folded dipole where the parallel wire section is shorter than the primary wire section; this gives more flexibility in impedance matching.
To obtain a second resonance with the folded dipole, a second folded element 24 is positioned inside the loop of the primary element. The second folded element is approximately ½ wavelength long at the desired second frequency. Like the primary element 20 the impedance of the second element can be adjusted by varying the width of the loop and the diameters of the wires. The second element is not attached to the feed point of the first element and is in effect a closed loop. A unique feature of the design is that a second folded dipole element 24 is parasitically coupled to the first folded element 22 by placing it in the actual loop of the first folded element 22. The impedance of the second element 24 can be varied by the actual placement in the primary element's loop. The second element 24 does not need to be a folded element but can be a single wire element or a loop. A third or more elements at different frequencies may be added into the primary element to allow more frequency responses to make a multi-frequency antenna.
In
Referring to
It has been found effective to print the metal antenna on an insulative printed circuit board. To this end, in
As illustrated in
Thus the antenna of the present is extremely useful in low profile antenna technology. The antennas may provide operation in various frequency bands, including but not limited to the cellular, PCS, and GPS bands.
Although illustrative embodiments of the invention have been shown and described, it is to be understood that various modifications and substitutions may be made without departing from the novel spirit and scope of the present invention.
Claims
1. An antenna which comprises:
- a primary folded dipole element;
- a feed for said primary folded dipole element;
- said primary folded dipole element being operable to resonate at a first frequency range;
- said primary folded dipole element being rectangular and including dipole extensions extending from said rectangle to provide a desired resonance;
- a first parasitic dipole element;
- said first parasitic dipole element being rectangular;
- said first parasitic dipole element being located within said primary folded dipole element and spaced therefrom;
- said first parasitic dipole element being operable to resonate at a frequency range higher than said first frequency range;
- said primary folded dipole element including dipole extensions extending from said rectangle to provide a desired resonance;
- said primary folded dipole element with said extensions and said first parasitic dipole element being formed of metal on a printed circuit board, said extensions having a distal end with said extensions increasing in width toward said distal end to provide a wider band width response.
2. An antenna which comprises:
- a primary folded dipole element;
- a feed for said primary folded dipole element;
- said primary folded dipole element being operable to resonate at a first frequency range;
- a first parasitic dipole element;
- said first parasitic dipole element being located within said primary folded dipole element and spaced therefrom;
- said first parasitic dipole element being operable to resonate at a frequency range higher than first frequency range;
- said primary folded dipole being rectangular and including dipole extensions extending from said rectangle to provide a desired resonance;
- said primary element with said extensions and said parasitic element being formed of metal on a printed circuit board, said extension having a distal end with said extensions increasing in width towards said distal end to provide a wider band width response.
3. An antenna which comprises:
- a primary folded dipole element;
- a feed for said primary folded dipole element;
- said primary folded dipole element being operable to resonate at a first frequency range;
- said primary folded dipole element being rectangular;
- a first parasitic dipole element;
- said first parasitic dipole element being located within said primary folded dipole element and spaced therefrom;
- said first parasitic dipole element being operable to resonate at a frequency range higher than said first frequency range;
- said primary folded dipole element and said first parasitic dipole element being formed on a printed circuit board;
- said primary folded dipole element Including dipole extensions extending from said rectangle to provide a desired resonance, said primary folded dipole with said extensions and said parasitic dipole element being formed of metal on said printed circuit board;
- said extensions having a distal end with said extensions increasing in width toward said distal end to provide a wider band width response.
4. An antenna which comprises:
- a primary folded dipole element;
- a feed for said primary folded dipole element;
- said primary folded dipole element being operable to resonate at a first frequency range;
- a first parasitic folded dipole element;
- said first parasitic folded dipole element being located within said primary folded dipole element and spaced therefrom;
- said first parasitic folded dipole element being operable to resonate at a frequency range higher than first frequency range;
- said primary folded dipole being rectangular and including dipole extensions extending from said rectangle to provide a desired resonance; and
- said primary element with said extensions and said parasitic element being formed of metal on a printed circuit board and said extensions having a distal end with said extensions increasing in width toward said distal end to provide a wider bandwidth response.
5. An antenna which comprises:
- a primary folded dipole element;
- a feed for said primary folded dipole element;
- said primary folded dipole element being operable to resonate at a first frequency range;
- said primary folded dipole element being rectangular;
- a first parasitic folded dipole element;
- said first parasitic folded dipole element being located within said primary folded dipole element and spaced therefrom;
- said first parasitic folded dipole element being operable to resonate at a frequency range higher than said first frequency range;
- said primary folded dipole element including dipole extensions extending from said rectangle to provide a desired resonance, said primary folded dipole element with said extensions and said first parasitic folded dipole element being formed of metal on a printed circuit board;
- said extensions having a distal end with said extensions increasing in width toward said distal end to provide a wider bandwidth response.
3229298 | January 1966 | Morgan |
3689929 | September 1972 | Moody |
3813674 | May 1974 | Sidford |
6466178 | October 15, 2002 | Muterspaugh |
6791500 | September 14, 2004 | Qi et al. |
20060220869 | October 5, 2006 | Kodukula et al. |
05-283926 | October 1993 | JP |
Type: Grant
Filed: Sep 2, 2005
Date of Patent: Nov 6, 2007
Patent Publication Number: 20060061515
Assignee: Mobile Mark, Inc. (Schiller Park, IL)
Inventors: Jerry C. Posluszny (LaGrange Park, IL), Randy C. Posluszny (Lyons, IL)
Primary Examiner: Hoanganh Le
Attorney: Seyfarth Shaw LLP
Application Number: 11/218,755
International Classification: H01Q 9/26 (20060101);